It's not at all unreasonable or unkind to ask person 1 to keep it down or hang up. Whether you are the presenter or not it's not out of line to say something like "Yo, Person 1, we seem to be picking up a lot of noise from your mic. Can you hang up and call back from a quieter environment?"

"If we ever get to heaven boys, it aint because we aint done nothin' wrong" - Kris Kristofferson

"One of the things I love about CPS is the frank and enthusiastic dysfunction here. God help me, I do love it so." – OldWorldSwine

"I'd like to put a hook in that puppet and swing it through a bunch of salmon!" - durangopipe